Heat exchanger



l. J. KNuDsoN w HEAT EXCHANGER Aug. 17, 1937,

Filed Aug. 30, 1935 INVENTOR ATTORNEY Patented Aug. 17, 1937 UNITEDsTATEs Pzi'rrzly'r OFFICE 2,090,208 HEAT EXCHANGER Irving J. Knudson,Kenilworth, Ill. Application August 30, 1933, Serial No. 687,427

1 Claim.

This invention relates to a heat exchanger adapted for use either as aheating device or as a cooling device.

Temperatures of rooms or the like have here- '5 tofore been afiected bythe use of suitable heat exchangers. Radiators or other heating deviceshave been used for increasing thetemperature and evaporators or the likehave been used for decreasing the temperature. These devices have beenused separately, and sometimes they have been used conjointly, but theyhave always been constructed as separate units and this has involved aduplication of devices and parts for heating and cooling, has requiredmore space than is usually available in residential buildings,- and hasrendered installation expensive.

The primary object of my invention is to provide a heat exchanger in as'ngle unit adapted forA heating or for cooling and whichcan becompactly made and installed in much less space and more convenientlythan has heretofore' been possible with separate heating and coolingunits.

The rate of change in temperature of a fluid such as air flowing throughor past a'heat exchanger is proportionate to the surface area of theexchanger with which the fluid may contact,

and a further object of my invention is to provide a compact heatexchanger unit adapted for heating or for cooling wherein the entirestructure provides a contact surface for the fluid and therebycontributes to the emciency of the unit when used forheating or whenused for cooling.

A further object of the invention is to provide a heat exchanger in asingle unit with a heating conduit and a coming-conduit and with flnsengaged with both conduits whereby the heating conduit and nnsconstitute an extension of the contact surface of the cooling conduitand assist the cooling conduit in cooling a fiuid passedA through theexchanger when a cooling medium flows through the cooling conduit, andwhereby the cooling conduit and fins constitute lan extension of thesurface of the heating conduit and assist the heating conduit `inheating a fluid passed through the exchanger .when a heating mediumfiows through the heating conduit.

Selected embodiments of the invention are illustrated in theaccompanying drawing wherein Fig. 1 is a front .elevation, partly.broken away,

showing one form of my invention;

Fig. 2 is 'an end view substantially on the line 2-2 on Fg. 1; w

Fig. 3 is a view similar to Fig. 2 showing anx.65 other form ofconstruction;

Fig. 4 is a horizontal sectional view on the line 5-5' on Fig. 3; z

Fig. 5- is a detail perspective view illustrating another form of theinvention; and

Fig. 6 is a detail perspective view illustrating 5 another form of theinvention.

In the preferred form of the invention, the heat exchanger is preferablyarranged in a cabinet 5 which is open at the bottom and has a restrictedopening 6 in its front wall provided with a reticu- 10 lated covering 1.A fan or blower is provided in the cabinet 5 to circulate the air, thatis, cause the air to fiow or pass through or past the exchanger, ornatural circulation of the air as induced by the temperature change inthe ex- 15 changer may be relied upon to effect circulation. Two blowershaving housings 5' and 6' are mounted in the upper part of the `cabinet5 with the inlets thereof positioned to receive air flowing from theexchanger. The outlets 'l' and 8' 20 of the housings face toward theopening 6 so that air discharged from the housings passes out throughthe reticulated covering 1. A motor 9' is positioned between thehousings 5' and 6' and drives the fans mounted in the housin'gs, and 25this motor is Controlled by switch means (not shown) suitably located onthe cabinet 5.

In the form of the invention shown' in Figs. 1 and 2, a plurality oflarge plates 8 are. arranged in spaced parallel relation and pipes 9,IO, and |2 for a heating medium are extended through all of the plates.An inlet pipe`l3, having a valve |3' therein, is connected to one end ofthe pipe IO and the other end of this pipe is connected to the adjacentend of pipe ll by the con- 35 nection M. The opposite end of the pipe isconnected to the adjacent end of the pipe IZ by a connection |5, theopposite end of the pipe |2 is connected to the adjacent end of the pipe9 by a connection IG, and the opposite end of the pipe 40 9 is connectedto an outlet pipe |1. The four pipes thus being connected provide asingle conduit through which a. heating medium-may be circulated, and itis to be understood that the number of pipes forming the conduit may bein- 5 creased or decreased according to the capacity i requiredfor theheat exchanger unit. I have referred to the pipe |3 as the inlet and thepipe l'l as the outlet but the pipe l'l may be used as the 50 inlet andthe pipe |3 as the outlet, if desired and if this is done 'a valve, likethe valve |3', will be provided in the pipe I'l. The inlet pipe |3 leadsfrom a suitable source of heating medium such as steam, hot water or thelike and the outlet pipe 66 leads back to the source desired.

Pipes IB, |9, and 20 are extended through the plates 8 near the bottomedges thereof, pipes 2|, 22, and 23 are extended through the plates nearthe top edges thereof, and pipes 24, 25, and 26 are extended through theplates substantially midway between the top and bottom thereof. An inletpipe 21, having a valve 21' therein, is connected to one end of the pipe23 and a connection 28 connects the opposite end of pipe 23 with'theadjacent end o`f pipe 22, a connection 29 connects the other end of pipe22 with the adjacent end of pipe 2|, a connection 30 connects theopposite end of pipe 2| with the adjacent end of pipe 24, a connection3| connects the opposite end of pipe 24 with the adjacent end of pipe25, a connection 32 conneets the opposite end of pipe 25 with theadjacent end of pipe 26, a con- 20 nection 33 connects the opposite endof pipe 26 with the adjacent end of pipe 20,, a connection 34 connectsthe opposite end of pipe 20 with the adjacent end of pipe IS, aconnection 35 connects or elsewhere, as may be the opposite end of pipeI9 with the adjacent end of pipe |8, and an outlet pipe 36 is connectedto the opposite end of pipe IB. These pipes being thus connectedconstitute a continuous conduit through which a cooling medium may becirculated. While I have designated the pipe 21 as the inlet and thepipe 36 as the outlet, the pipe 36 may be used as the inlet and the pipe21 as the outlet, if desired, and if this is done a valve, like thevalve 21', will be provided in the pipe 36. The inlet pipe 21 leads froma suitable source of cooling medium such as a refrigerant used in directexpansion or fiooded refrigerating systems, or cooled brine, or thelike, and this cooling medium is circulated through the conduit andfiows out through the outlet pipe 36 back to the source or elsewhere, asdesired.

The valves in the inlet pipes are seleetlvely and alternately opened andclosed so that a heating medium may be circulated through the heatingconduit without circulating a cooling medium 45 through the coolingconduit or so that a cooling medium may be circulated through thecooling medium without circulating a heating medium through the heatingconduit, the medium selected depending upon whether it is desired 50 toraise or lower the temperature of air circulated through the exchanger.i

The plates 8 constitute fins for the conduits and these conduitspreferably extend through all of the fins and the fins are arranged ininti- 55 mate contact with the conduits to constitute an extension ofthe surfaces of the conduits. This may be acccmplished by extending theconduits through openings in the fins and subsequently expanding theconduits into tight engagement 60 with the edges of the openings; or thefins may be united with the conduits by brazing, soldering, galvanizing,tinning, welding or otherwise to obtain intimate contact of the finswith the conduits. Since the heating and cooling conduits 65 preferablyextend through all of the fins, the heating conduit as well as the finsconstitute an extension of the surface area of the cooling' conduct andassist in cooling air or other fluid passed through the exchanger when acooling 70 medium is circulated through the cooling conduit,

and the cooling conduit as well as the fins constitute an extension ofthe surface area ofthe heating conduit and assist in heating air orother fluid passed through the exchanger when a heat- 75 ing medium iscirculated through the heating in slightly overlapped `fins whereas inthe conduit. 'I'hus, the arrangement of the heating and cooling conduitsin the fins is not only important for making a single unit for heatingand for cooling, and for making the unit in a conpact form for economyin manufacture and convenience in installation, but it has the furtherutility of increasing the contact surface for air or other fluid to betreated by utilizing the cooling conduit as an extension of the contactsurface for the heating medium and the heating 'conduit as an extensionof the contact surface for the cooling medium, whereby the efliciency ofthe unit is increased without duplication of parts.

The rate of heat absorption is less than the rate of heat transmissionand consequcntly I make the cooling conduit longer than the heatingconduit.

In Figs. 1 and 2, the pipes 9, IO, ll, and |2 for the heating conduitare preferably located on the diagonals of the fin plates, and thesepipes as well as the pipes for the cooling conduit are preferablydisposed symmetrically as shown in Fig. 2 or they may be otherwisedisposed to meet special conditions or for other reasons. While it isbelieved that the type of heat exchanger illustrated will besatisfactory for general purposes,r it is recognized that the structureof buildings and other conditions may make it necessary to change thesize and shape of the heat exchanger for satisfactory use and changes ofthis kind in the size, location and arrangement of the conduits and finplates may be made as required while still retaining the and advantagesof the invention. i

The form of invention illustrated in Figs. 3 and 4 is similar to thatillustrated in Figs. 1 and 2 except that instead of a single large plate8, as shown in Fig. 2, I provide a plurality of small plates formingseparate fins for each pipe of the conduits, and also show a differentarrangement of the heating conduit pipes. These heating conduit pipes31, 38, and 39 are arranged in side by side relation in the samehorizontal plane and they are joined by connections 40 and 4| to providea continuous conduit for the heating medium. Plates 42, 43, and 44 aremounted on the pipes 31, 38, and 39 respectively and these plates arearranged' in substantial parallelism and overlap in or about the mannervshown in Fig. 4. Pipes 45 to 52, inclusive, are arranged in parallelismand aboutthe pipes 31 to 39 and these pipes are joined by connections 54to 59 to form the cooling medium conduit. An inlet pipe 53 is connectedto the pipe 41 and an outlet pipe 6| is connected to the pipe 49. Asbefore explained, the pipe 6| may be the inlet pipe and the pipe 53 maybe the outlet pipe.

essential characteristics i A plurality of plates 62 to 69, inclusive,are

arranged, as hereinbefore described, upon the pipes to 52, inclusive, insubstantial parallelism with each other and with the plates 42 to 44.The plates 42, 43, and 44 are preferably arranged w position, as shown,and the plates 68 and 69 also preferably slightly overlap the plates 42and 44 but the other plates do not overlap, as shown in Fig. 3. Thisarrangement of the plates may, however, be changed as desired tooverlapped or spaced relation as may be desirable.

These plates form fins on the heating and cooling conduits but in thisembodiment each pipe of the conduits carries its own independentconstruction of Fig. 2 the fins are common to all of the pipes. All ofthe fins in Fig. 2 will be heated by conduction from theheating conduitor cooled by conduction from the cooling conduit whereas in Fig. 3 onlythose fins on the heating conduit will be heated by conduction therefromand only those fins on the cooling conduit will be cooled by condu'ctiontherefrom, but all of the fins are arranged in close relation and thosefins which are not heated or cooled by conduction will '2a heated orcooled by radiation, and in this way the cooling conduit and the finsthereon will assist in heating when a'heating medium is circulatedthrough the heating conduit and the heating conduit and the fins thereonwill assist in cooling when a cooling medium is circulated through thecooling conduit.

In the embodiment of Fig. 5, a plurality of plates 10 to 13 are arrangedin series, a heating pipe 14 for each series passes through the platesthereof, and the ends of these pipes are connected by headers 15.Cooling pipes 16 also extend through the plates of each series and areconnected by headers 18 and 19. The heating pipes with their headersconstitute a heating conduit and the cooling pipes with their headersconstitute' cooling conduits, and these conduits are connected withsources of supply of heating and cooling mediums. 'I'he'plates of eachseries 'constitute fins for the pipes passing therethrough,

and whereas the series of flns and pipes are spaced apart slightly theheating conduit and the cooling conduits pass through the fins of eachseries so that the cooling conduit and the fins constitute an extensionof the contact surface of the heating conduit for heating and theheating conduit and the fins constitute an extension of the coolingconduits for cooling.

In Fig..6, a plurality of plates 80 with central openlngs 8| arearranged on cooling pipes 82 and form fins therefor, and a plurality ofplates 83 are arranged within the openings 82 on heating pipes 84 andform fins therefor. The pipes 82 may be joined by connections or headersto form a continuous cooling conduit and the pipes 84 may be jolned byconnections or a header to form a continuous heating conduit. In thisform of invention the cooling conduit and its fins will be heated byconduction from the heating conduit and its fins and the heating conduitand its fins will be cooled by conduction from the cooling conduit andits fins.

While I have illustrated and described preferred forms of my invention,it is to be understood that these are capable of Variation andmodification and I therefore do not wish to be limited to the precisedetails set forth but desire to avail myself of such changes andalterations as fall within the purview of the following claim.

I claim:

A heat exchanger comprising a plurality of series of fins, each seriesof fins including a plurality of fins arranged in face-to-face spacedapart relation, the series of fins being arranged in spaced apartsuperimposed relation one from the other, a heating conduit extendingthrough each series of fins substantially midway between the ends of thefins, a cooling conduit extending through each series of finssubstantially midway between the heating conduit and one end of each finof the series, another cooling conduit extending through each series offins substantially midway between the heating conduit and the other endof each fin of vthe series, said heating and cooling conduitsterminating slightly beyond the outwardmost fins at each end of eachseries of fins, the heating conduits being in substantial alignment witheach other, the respective cooling conduits on opposite sides of saidheating conduit being in substantial allgnment with each other, headersrespectively oonnecting the aligned conduits at opposite ends thereofwhereby the temperature of a heating medium circulated from a header atone end of the heating conduits through said heating conduits will besubstantially uniform in all conduits and the temperature of a coolingmedium circulated through each set of aligned cooling conduits from aheader interconnecting corresponding ends of said conduits will also besubstantially uniform, said conduits all being in heat exchangingrelation with the fins through which they are extended whereby theheating conduits and the'fins will assist the cooling conduits incooling a fluid passed through the exchanger when a 'cooling medium iscirculated through the cooling conduits, and the cooling conduits andthe fins will assist the heating conduits in heating a fluid passedthrough the exchanger when a heating medium is circulated through theheating conduits.

IRVING J. KNUDSON.

